开云体育

From the picture it looks like you are missing installation of the capacitor C-525, labelled "271" that goes between L513 and X201. Did you have a cap left over? Sandy KB3EOF

I think the reason is that they are not driven hard enough just by the Si5351. Maybe add a driver? 73 Alan GZFQ

I looked, unfortunately the attachments are gone. After 100MB of attachments old ones get deleted. Old messages are not always useful. Good information needs to be saved elsewhere. 73 Alan G4ZFQ

I probably should've thought a bit more and add that, when talking about return loss and network impedance characteristics, we tend to think about those within the passband of interest, but when it

One correction. That capacitance is not a maximum spec, but rather a test condition. My mistake. Still, I think the total capacitance may be too much for the chip to swing at 28 MHz. JZ

Great answer, Ryoji, thanks! JZ

Jerry wrote: I’m currently working on a UL3s for 10 meters and decided to solder in BS170s in the remaining slots and the output power actually went way down. Is this due to parallel capacitance

JZ, that's a reasonable question. When the author says RL, that is a pure resistive load. They use series or parallel LC network to express the total load impedance. In order to achieve a certain

I cut mine out on the PCB mill at work, so I get bare copper and not the purple solder mask. Chuck KB3ASW

these are my toroids, the number of windings look ok to me but something is causing a low frequency response. have I wound them wrong? Do I remove a turn?

Ryuji, The dissertation has much to recommend it, but it leaves me with some open questions. It focuses on microwave frequency PA designs for mobile telecom, and discusses output tank circuits only

Hello Hans, Thank you for the response. For the current QMX, using the unused 0 BPF selection on IC402 might be possible.? That could be set up with jumpers to bypass the BPF.? That does take up

Chris, that is one possible way to do a measurement if the detector response can be sufficiently linearized in post-ADC computation. One downside is that the amplifier's output impedance and the load

Hans: I think it could be done if you run the PAs at low voltage (commanded through Q507) and sweep the frequency while reading the forward power through T507 with the future SWR firmware.? Obviously

Ok Jerry - I thought this thread was Hans expressing his viewpoint and various tradeoffs made as the kit designer. Obviously, those who are doing user-level modifications have greater freedom in terms

Ryujii, My apologies if my reply was off topic. Maybe it was only on-topic for me :-). I thought it was about the merits of the BS170 and my intention was to point out an apparent frequency limit

Hello Evan It's a difficult thing. There's no BPF bypass and no way to separate the response of the BPF from that of the LPF. On QMX you could sort of do it crudely by measuring power output power

Hi all, I'm back from a very nice holiday in EA6-land (Mallorca Island), including several SOTA and POTA activations, using either my KX3 or QCX Mini 17m/20m. This is a reminder that we have the QCX

Thanks Ross, that was a quick reply. I wonder if anyone who inquired about the topic can find it here. Unfortunately, they use the forum as a messenger, instead of entering what they are interested in